A method and device of this type are disclosed by U.S. Pat. No. 5,241,933. It describes a method and a device for monitoring a high-pressure circuit when working with a common-rail system. In the case of the device it describes, the pressure prevailing in the rail is regulated. If the manipulated variable of the pressure control loop lies outside of a specifiable range, the device recognizes the existence of an error.
In addition, devices are known, where the existence of an error is inferred on the basis of the pressure prevailing in the rail. The pressure is thereby compared to lower and upper limiting values, and the existence of errors is recognized when the pressure lies outside of the specified range of values.
The drawback of these arrangements is that an error is first recognized in response to a substantial pressure drop.